An Ohio woman who authorities say killed four men with lethal doses of fentanyl in order to rob them pleaded not guilty to murder charges on Monday.

Rebecca Auborn entered her plea in court accompanied by her attorney, Mark Hunt.

Authorities said there are likely more victims, and the investigation is ongoing.

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Rebecca Auborn sits in a Columbus, Ohio courtroom with her attorney

This photo shows Rebecca Auborn, accused of killing four men by fatally drugging them to steal their possessions, sitting in a Franklin County courtroom in Columbus, Ohio alongside her attorney on Monday, Oct. 30, 2023. ((AP Photo/Samantha Hendrickson))

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Auborn, 33, of Columbus, is accused of killing the men and nearly killing a fifth man after meeting them for sex in Columbus between December 2022 and June 2023. Authorities did not identify the men.

Auburn had already pleaded not guilty last month to murder and drug-related charges in connection with one of the men's deaths.

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She will continue to be held without bond.